Rome University La Sapienza, Roma
INFN/LNF, Frascati (Roma)
ENEA C.R. Frascati, Frascati (Roma)
LBNL, Berkeley, California
Velocity bunching (or RF compression) represents a promising technique complementary to magnetic compression to achieve the high peak current required in the linac drivers for FELs. Here we report on recent progress aimed at characterizing the RF compression from the point of view of the microbunching instability. We emphasize the development of a linear theory for the gain function of the instability and its validation against macroparticle simulations that represents a useful tool in the evaluation of the compression schemes for FEL sources.
INFN/LNF, Frascati (Roma)
ENEA C.R. Frascati, Frascati (Roma)
Rome University La Sapienza, Roma
LBNL, Berkeley, California
The effects of microbunching instability for the SPARX accelerator have been analyzed by means of different numerical simulation codes and analytical approach. The laser heater counteracting action has been also addressed in order to optimize the parameters of the compression system, either hybrid RF plus magnetic chicane or only magnetic, and possibly enhance the FEL performance.
Rome University La Sapienza, Roma
INFN/LNF, Frascati (Roma)
The SPARX-FEL project is meant to provide ultra high peak brightness electron beams, with the energy ranging between 1.5 - 2.4 GeV, in order to generate FEL radiation in the 0.6-40 nm range. The construction will start with a 1.5 GeV Linac; besides the basic S-band technology the C-band option is also presently under study. Both RF-compression and magnetic chicane techniques are foreseen to provide the suitable electron beam to each one of the three undulator systems which will generate VUV-EUV, Soft X-Rays and Hard X-rays radiation respectively. Dedicated beamlines will distribute the beam to the downstream undulators for applications in basic science and technology. In this paper we present the status of the project funded by the Italian Department of Research, MIUR, and by the local regional government, Regione Lazio, that foresees the construction of a user facility inside the Tor Vergata campus by collaboration among CNR, ENEA, INFN and the Università di Tor Vergata itself.
INFN/LNF, Frascati (Roma)
Istituto Nazionale di Fisica Nucleare, Milano
Università di Roma I La Sapienza, Roma
INFN-Roma II, Roma
Università di Roma II Tor Vergata, Roma
University of Rome La Sapienza, Rome
Rome University La Sapienza, Roma
ENEA C.R. Frascati, Frascati (Roma)
The region of the spectrum from 0.3 to 5 THz is of great interest for several experiments in different areas of research. A THz radiation source can be produced at SPARC as coherent transition radiation emitted by either a compressed or longitudinally modulated beam intercepting a metal foil placed at 45° with respect to the beam propagation. Results on the characterization of the THz source at SPARC are described in the paper.
INFN/LNF, Frascati (Roma)
CERN, Geneva
BINP SB RAS, Novosibirsk
Recently the peak luminosity achieved on the DAΦNE collider has been improved by almost a factor 3 by implementing a novel collision scheme based on large Piwinski angle and Crab-Waist. This encouraging result opened new perspectives for physics research and a new run with the KLOE-2 detector has been scheduled to start by spring 2010. The KLOE-2 installation is a complex operation requiring a careful design effort and a several months long shutdown. The high luminosity interaction region has been deeply revised in order to take into account the effect on the beam caused by the solenoidal field of the experimental detector and to ensure background rejection. The shutdown has been also used to implement several other modifications aimed at improving beam dynamics: the wiggler poles have been displaced from the magnet axis in order to cancel high order terms in the field, the feedback systems have been equipped with stronger power supplies and more efficient kickers and electrodes have been inserted inside the wiggler and the dipole vacuum chambers, in the positron ring, to avoid the e-cloud formation. A low level RF feedback has been added to the cavity control in both rings.
INFN/LNF, Frascati (Roma)
Istituto Nazionale di Fisica Nucleare, Milano
INFN-Roma II, Roma
ENEA C.R. Frascati, Frascati (Roma)
University of Rome La Sapienza, Rome
INFN-Roma, Roma
UCLA, Los Angeles, California
JASRI/SPring-8, Hyogo-ken
PSI, Villigen
The primary goal of the SPARC project is the commissioning of the SASE FEL operating at 500 nm driven by a 150-200 MeV high brightness photoinjector. Additional experiments are foreseen also in the HHG Seeded configuration at 266, 160 and 114 nm. A second beam line hosting a THz source has been recently commissioned. The recent successful operation of the SPARC injector in the Velocity Bunching (VB) mode has opened new perspectives to conduct advanced beam dynamics experiments with ultra-short electron pulses able to extend the THz spectrum and to drive the FEL in the SASE Single Spike mode. Moreover a new technique called Laser Comb, able to generate a train of short pulses with high repetition rate, as the one required to drive coherent plasma wake field excitation, has been tested in the VB configuration. The energy/density modulation produced by an infrared laser pulse interacting with the electron beam near the cathode has been also investigated. In this paper we report the experimental results obtained so far and the comparison with simulations.
INFN/LNF, Frascati (Roma)
Istituto Nazionale di Fisica Nucleare, Milano
Rome University La Sapienza, Roma
ENEA C.R. Frascati, Frascati (Roma)
In the frame of the SPARC-X project, the energy of the Photo-Injector SPARC, in operation at INFN-LNF, will be upgraded from 180 to 250 MeV by replacing a low gradient S-band traveling wave accelerating section with two C-band units, designed and developed at LNF. The new system will consist of a 50 MW klystron, supplied by a pulsed modulator, to feed the high gradient C-band structures through a RF pulse compressor. This paper deals with the design of the full system, the C-band R&D activity and study of the related beam dynamics.